A door lock apparatus for a vehicle generally includes a latch mechanism which brings a vehicle door to a closed state (latched state) or an openable state (unlatched state), and a lock mechanism which makes a changeover between an unlocked state for enabling the latch mechanism to shift from the latching state to the unlatching state, and a locked state for disabling the latch mechanism from shifting from the latching state to the unlatching state.
One type of the above-mentioned lock mechanism includes an opening mechanism section having an outside opening lever, an inside opening lever, an opening link, and an active lever; an electric actuator section for driving the opening link to an unlocking position or a locking position via the active lever; and a lever mechanism section for driving, independent of the electric actuator section, the opening link to the unlocking position or the locking position via the active lever. Such a type of the lock mechanism is disclosed in, for example, Japanese Patent Application Laid-Open (kokai) No. 2011-26826 (Reference Document 1).
When the opening link is in the unlocking position, the latch mechanism can shift from the latching state to the unlatching state through operation of the outside opening lever or the inside opening lever in association with an opening operation of an outside handle or an inside handle provided on a vehicle door, so that the closed vehicle door can be opened. When the opening link is in the locking position, the latch mechanism cannot shift from the latching state to the unlatching state through operation of the outside opening lever or the inside opening lever in association with the opening operation of the outside handle or the inside handle.
The lever mechanism section of the vehicle door lock apparatus described in Reference Document 1 mentioned above is connected, via a rod, to a key cylinder disposed in an outside handle of a vehicle door and is configured such that the active lever performs a locking operation or an unlocking operation in response to a turning operation of the key cylinder. In a locking operation (movement from an unlocking position to a locking position) of the active lever, the opening link is driven from the unlocking position to the locking position. In an unlocking operation (movement from the locking position to the unlocking position) of the active lever, the opening link is driven from the locking position to the unlocking position.
The lever mechanism section includes an outside locking lever (may be called a key rotor) linked to the rod and rotatably mounted to a housing mounted within the door, and a key lever which is rotatably mounted within the housing, rotates together with the outside locking lever, and is linked to the active lever. The key lever includes a hub portion which is rotatably supported by the housing and the outside locking lever and which is connected to the outside locking lever in a torque transmissible manner; a first arm portion which extends radially outward from the hub portion and can be engaged with a first engagement portion of the active lever; and a second arm portion which extends radially outward from the hub portion and can be engaged with a second engagement portion of the active lever.
Meanwhile, the vehicle door lock mechanism described in the above Reference Document 1 has a fragile portion provided between the hub portion of the key lever and the second arm portion. The fragile portion is breakable when the rod is pushed toward the key lever with a force of a predetermined value or greater. Thus, when the rod is pushed toward the key lever with a force of a predetermined value or greater, the key lever breaks at the fragile portion. In such a breakage condition, in the key lever, rotation is not transmitted from the hub portion to the second arm portion. Accordingly, even when the outside locking lever is rotated in an unlocking direction in response to a turning operation of the key cylinder, the active lever in the locking position is not pivotally moved in the unlocking direction, thereby maintaining the locked state. Therefore, the door lock apparatus can be enhanced in anti-theft function.
Also, in the vehicle door lock apparatus described in the above Reference Document 1, the housing has a breakage aid portion which aids breakage at the fragile portion of the key lever when the rod is pushed toward the key lever with a force of a predetermined value or greater. Thus, as compared with the case where the housing does not have the breakage aid portion, when the rod is pushed toward the key lever with a force of a predetermined value or greater, breakage at the fragile portion of the key lever can be ensured, whereby the anti-theft function of the door lock apparatus can be further enhanced.
In the vehicle door lock apparatus described in the above Reference Document 1, the housing does not have therein a space for allowing the hub portion of the key lever to move in a vehicle interior-exterior direction. Thus, in order to effect breakage at the fragile portion of the key lever, the housing must be deformed or broken toward the outside of the housing. Therefore, a space for allowing deformation or breakage of the housing must be provided at the outside of the housing, thereby limiting mountability on a vehicle.